3rd generation partnership project (3GPP) Long Term Evolution (LTE) has introduced Group Communication System Enablers (GCSE) to transmit data to a plurality of User Equipments (UEs) for urgent communication, such as a public disaster.
In 3GPP Release 12, a group of UEs uses a Multimedia Broadcast Multicast Service (MBMS) to receive group communication.
The MBMS has been designed to provide media contents for a mobile TV in a large-scale planned area (for example, an MBSFN area). The MBSFN area is a predetermined nonadjustable area. Further, the MBSFN area cannot be dynamically adjusted according to user distribution. MBMS transmission occupies an entire system bandwidth. Furthermore, even if not all radio resources are used within a frequency domain, unicast and multiplexing are not allowed in the same subframe.
As described above, the MBMS occupies the entire system bandwidth and cannot be dynamically adjusted according to the number of groups or traffic load of the groups because the MBMS is static predetermined nonadjustable area. This results in inefficiency of transmission of group communication data from an evolved Node B (eNB) to a plurality of UEs.